This invention relates to vapor-liquid contacting in apparatus of the cross-flow type, e.g. in a fractional distillation column.
In such systems, mass transfer is accomplished by liquid flow across horizontal orificed trays through which vapor is forced. Column throughput and efficient mass transfer are limited by a number of factors including priming, entrainment of the liquid droplets in the vapor flow, downcomer flooding, hydraulic gradient, weeping, transition to spray regime operation, non-plug flow of liquid across the trays, and liquid back-mixing.
Webster, U.S. Pat. No. 3,467,365, shows a layer of expanded metal attached to a sieve tray to give gas entering the vapor/liquid dispersion a component of velocity in the direction of the liquid flow path.
Mix and Erickson, U.S. Pat. No. 3,887,665, shows layers of wire mesh in contact with the tray which serve to limit the oscillations in the vapor/liquid dispersion at the tray surface. A similar function is performed by vertical sheets above the tray in Mix ('665) and Mix, U.S. Pat. No. 4,105,723.
In both aforementioned Mix patents, zigzag woven wire mesh is placed above the vapor/liquid dispersion to recover entrained liquid droplets. In Mix ('732), this zigzag deentrainment mesh is placed on top of an expanded metal support.
Bruckert and Wang, U.S. Pat. No. 3,282,576, shows an inlet weir having a perforated and inwardly and downwardly sloping surface to initiate froth formation in the entering liquid.
Uitti and Carson, U.S. Pat. No. 3,700,216 shows an inwardly and upwardly sloping inlet weir, forming the top of a vertical vapor inlet slot positioned above the tray, to initiate froth formation in the entering liquid.